Study On The Physical And Biological Properties Of Chitosan/Silk Fibroin/Multi-walled Carbon Nanotube Scaffolds

Objective: Periodontal disease is an inflammatory and destructive disease involving periodontal supporting tissue.With the destruction of periodontal supporting tissue and the absorption of bone tissue,tooth loss is eventually caused.Severe periodontitis patients are usually accompanied by serious bone defects,alveolar bone can be significantly absorbed horizontally,how to effectively restore bone defects is a difficult problem.In recent years,the rise and development of bone tissue engineering provides a new way for clinical treatment of bone defects.The aim of this study is to fabricate composite scaffolds made of chitosan/silk fibroin/multi walled carbon nanotubes(CS/SF/CNTs),detect their physicochemical properties,compare their efficacy to support proliferation and differentiation of the rat bone marrow mesenchymal stem cells(BMSCs)in vitro,and hope to provide new ideas for the regeneration of periodontal bone tissue.Material and Methods: CS/SF/CNTs were prepared by freeze-drying technique.The physical properties of the scaffold were tested by measuring the porosity,water absorption expansion rate and scanning electron microscope.The rat bone marrow mesenchymal stem cells were isolated and cultured and inoculated on scaffold materials,and the compatibility of cell and scaffold materials,cytotoxicity and osteogenic ability were observed by SEM and cell proliferation and alkaline phosphatase activity.Results: 1.The scaffold material was highly porous and stable.A typical scanning electron microscopy(SEM)images of the scaffold showed uniform porous structure with interconnected pore channels.When the multi-wall carbon nanotubes(CNTs)was increased from 0% to 9%(mass fraction),the porosity of scaffolds decreased from90.31 ± 4.23% to 81.26 ± 4.33%,and the water swelling rate decreased from 138.12 ±6.75% to 106.28 ± 5.41%.The porosity and water absorption rate of the composite scaffold with 3% carbon nanotubes were 89.51 ± 5.29% and 135.84 ± 4.42%,respectively,which was used in the following studies.2.The BMSCs were seeded on CS/SF/CNTs scaffold containing 3% carbon nanotubes for 24 h,the cells were observed to grow well and combine closely on the scaffold and the cell proliferation was obvious by scanning electron microscope.The cells were flat with pseudopodia and spread on the surface and pore of these scaffolds.3.The results of MTS showed that BMSCs can grow in both scaffolds of CS/SF/CNTs and chitosan / silk fibroin without carbon nanotubes(CS/SF).The proliferation rate of BMSCs in the CS/SF/CNTs and CS/SF scaffolds were significantly higher than that of BMSCs grew in the plates(P <0.05).It shows that CS/SF/CNTs and CS/SF scaffolds composite scaffold have good biocompatibility.4.The results of alkaline phosphatase activity test showed that CS/SF/CNTs scaffold could increase secretion of alkaline phosphatase in BMSCs,compared with the CS/SF stent and the blank control groups(P<0.05),Conclusion: 1.Silk fibroin solution,chitosan solution and multi-walled carbon nanotubes can be mixed and modify each other.stable CS/SF/CNTs composite scaffolds can be prepared by freeze-drying.2.The pore size and porosity of CS/SF/CNTs composite scaffold containing 3% carbon nanotubes were suitable for osteoblast growth,its water swelling rate is beneficial to cell growth and proliferation.CS/SF/CNTs composite scaffold has good biocompatibility,and can promote BMSCs to differentiate into bone.It is expected to be a potential scaffold material for tissue engineering.